Soil Properties

Soil
is an organized mixture of minerals, organic materials, living organisms, air
and water. Soil exhibits both Chemical and Physical properties. These are
influenced by the mineral matter of soil and the size of soil particles such as
sand silt and clay. By adding organic content to the soil its structure
and texture are improved.

Chemical Properties

Salinity

Information on salt tolerance
is important for proper soil management practices. Based on salt tolerance
level, soil can be split into three categories, they are

Salt
Tolerant Crops (6-8 mmohs / cm) e.g. Watermelon

Moderate
Salt Tolerant Crops (3-6 mmohs / cm) e.g. Tomato, Lemon

Salt
Sensitive Crops (1.5 – 3 mmohs / cm) e.g. Avocado, Cauliflower

Nutrients

Plants require a number of
essential nutrients for growth and development. Both soil and atmosphere can
provide these nutrients. Some of these are need in larger amount ( macro
nutrients such asN/P/K) and some are in lesser amount (
micro nutrients such as Mn / Fe / Bo / Cu / Zn)

Like the temperature of the
human body, soil pH implies certain characteristics that might be associated
with soil. A soil pH of 7 is considered as neutral. Greater than 7
indicates alkaline and less than 7 indicates acidic.

Soil pH affects the quantity, activity and types of micro-organisms in soils
which in turn influence decomposition of crop residues, manures and other
organics. Majority of plants prefer pH between 6.5 to 8.5

Soils in wet climate tend to be acidic. Soils in high rainfall area tend
to be acidic because of leaching. Acid soils can be improved by adding
lime to soil.

Soil in dry climate tends to be alkaline. Lack of rainfall will not flush
the nutrients out of soil and they remain within soil. In extreme cases
this leads to salinization, in which soil contain too many salts, which prevent
the growth of many crops.

Physical Properties

Water Table

Availability
of water at a certain depth in the soil is called Water Table. High water
table leads to decline in vegetable and fruit crops due to logging conditions.
Water table should be less than 2 meters throughout the year.

Soil Depth & Texture

More
organic matter in soil will help vegetable and fruits to grow healthy and
require medium textured soil.

Soil Temperature

In
cold soils, chemical and biological activities are slow and availability of
nutrients is limited. Temperature should be 26 – 320 degree Celsius for
successive growth of Horticulture crops. Low temperature will affect the
transport of water and nutrients.

Soil structure and Aeration

Soil
structure is the key and has to be examined properly. It also varies in
different layers. Aeration is required for growing aerobic organism in
the soil to promote metabolic activities of these organisms.

Well
drained soil is required for proper aeration and drainage. Extreme wet
and dry soil should be avoided.